The present invention relates to an improved substrate for magnetic recording media, and more particularly relates to an improvement of a substrate used as a base material for magnetic recording media such as fixed magnetic disc recording devices.
It is conventionally employed to produce a magnetic recording medium by subjecting an Al or Al-base alloy substrate to anode oxidization to form an anode oxidized film thereon and depositing magnetic substance in pores in the anode oxidized film through precipitation.
To this end, 99.99% high purity Al or Al-base alloy including 3.5 to 4.5% by weight of reinforcing Mg is mainly used. This is mainly because other elements included in such Al or Al-base alloy do not form the anode oxidized film.
At deposition of the magnetic substance on such a substrate, there is unavoidable fluctuation in amount of the magnetic substance deposited in the pores in the anode oxidized film. This is because poor orientation of Al or Al-base alloy crystal in the substrate seriously hinders production of uniform barrier layers in the pores and resulting fluctuation in electric characteristics of the barrier layers induces corresponding fluctuation in rate and amount of deposition of the magnetic substance in the film pores.